An electric vehicle uses a power battery as a power source. A problem of the electric vehicle is how to improve a driving energy efficiency of the electric vehicle so as to extend a driving distance of the electric vehicle. An energy feedback is one effective measure to solve the above problem.
The energy feedback includes braking feedback and sliding feedback. During a sliding feedback of the electric vehicle, a motor controller controls an electric motor to feedback according to a calculated feedback torque, so as to charge the power battery, to increase the driving distance of the electric vehicle, and to reduce the pollutant emission and the wear caused by the mechanical brake.
Now, a sliding feedback control system and method of a vehicle has already been provided. The method includes: calculating an initial feedback torque value of the electric motor according to a current speed of the vehicle and a calibrated sliding deceleration; calculating a constraint feedback torque value of the power battery according to a temperature and a SOC (State of Charge) of the power battery; calculating a constraint feedback torque value of the electric motor according to a rotating speed of the electric motor; determining a final feedback torque value of the electric motor as a minimum of the initial feedback torque value of the electric motor, the constraint feedback torque value of the power battery and the constraint feedback torque value of the electric motor; and controlling the vehicle to recovery the sliding energy according to the final feedback torque value of the electric motor.
Although the above method can calculate the final feedback torque value of the electric motor to improve the efficiency of recovering the sliding energy of the vehicle, there are still some problems: a constraint feedback torque value of the motor controller is not calculated in the above method, and thus an influence of a current state of the motor controller on the feedback torque value of the electric motor is not fully considered, in which the current state of the motor controller influences an output power of the electric motor directly and thus influences the feedback torque value of the electric motor; in addition, the above method does not fully consider the influence of the current road condition and the working mode of the vehicle on the sliding feedback of the vehicle. Thus, the final feedback torque value of the electric motor calculated by the above method is not perfect, which may influence the sliding feedback efficiency of the vehicle.